Circuit maker and breaker



Oct. 9, 1956 R. E. ARKO CIRCUIT MAKER AND BREAKER Filed NOV. 17, 1952 2 Sheets-Sheet 1 FIG. I

FIG. 3

INVENTOR ROBERT E. ARKO ATTORNEY Oct. 9, 1956 Filed Nov. 1'7. 1952 CIRCUIT MAKER AND BREAKER R. E. ARKO FIG. 4

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INVENTOR ROBERT E. ARKO ATTORNEY nited States CIRCUIT MAKER AND BREAKER Robert Arko, Cicero, 111., assignor to Teletype Corporation, Chicago, Ill., a corporation of Delaware This invention relates to circuit makers and breakers and more particularly to instrumentalities for periodically closing a plurality of contacts in a circuit in successive fashion to effectuate a completion of the circuit for precise increments of time.

In the design of devices for use in making and breaking contacts contained in an electric circuit, it is a paramount requisite that the device close the contacts with a minimum degree of shock in order to eliminate any detrimental rebounding or bouncing of the contacts. Contacts subjected to rebounding or bouncing due to abrupt engagement shocks cause momentary interruption of the circuits in which they are contained and such interruptions are usually followed by arcing between the contacts. Arcing of the contacts ultimately results in a pitting of the contact element, hence in time, necessitating the replacement of the individual contact elements. Rebounding, bouncing or vibration of the contacts also accelerates the time at which the contacts must be replaced because of the in creased mechanical wear of the contacts due to the multi ple rapid engagements of the contact faces.

Another criterion which must be met in a properly designed circuit maker and breaker is the ability to make and break within finite increments of time. Further in the use of periodically operated circuit makers and breakers, it is essential that the period of closure of the contacts be accurately predictable and that the contacts close during predetermined regular intervals in the cycle of operation of the circuit maker and breaker.

It is a cardinal object of the present invention to provide a circuit maker and breaker which satisfies the prerequisites heretofore outlined.

It is another object of this invention to provide a rapidly operating circuit maker and breaker wherein the shock of engagement between contact elements is substantially eliminated by imparting a modified simple harmonic motion to the moving contact elements.

An object of this invention commensurate with the last object is the provision of means utilizing a plurality of periodically operating contacts, operating out of phase with one another, for completing a circuit or circuits for a period different from the period of operation of the individual contacts.

A further and more specific object of the invention resides in the utilization of a plurality of eccentrics to provide the motive force used to open and close a plurality of contacts, each of which is individually associated with one of the eccentrics.

An additional object of the invention is to connect the contacts in a series or parallel circuit and then vary the phase relationship between the eccentrics to vary the period of energization of the circuit.

Still another object of the invention is to provide a device for energizing a circuit to supply current to operate a piece of apparatus during accurately predictable and finite intervals of time.

' With these and other objects in view, the present invention contemplates a motor driven shaft having a pair of atent O eccentrics adjustably mounted thereon. Each eccentric imparts a simple harmonic motion to a strap which is connected to a contact unit of the type shown in the patent to W. J. Zenner No. 2,605,366, dated July 29, 1952. The contact units comprise an operating arm or T-lever and a pair of contact elements adapted to be engaged by the cross arms of the T-lever upon actuation of the T-lever by the eccentric driven strap. One contact in each contact unit together with the T-levers are connected in a series circuit to control the operation of an auxiliary piece of equipment. By varying the phase angle between the eccentrics, the duration of closure of the series circuit may be varied.

Another embodiment of the invention contemplates a connection of both contacts in each contact unit in parallel circuits to control the operation of two auxiliary pieces of equipment. Again, the period of energization of the circuits may be varied by changing the phase angle of the eccentrics.

Other objects and advantages of the present invention will be apparent from the following detailed description when considered in conjunction with the accompanying drawings wherein:

Fig. l is a schematic drawing of a circuit maker and breaker for controlling the energization of a series circuit in accordance with the principles of the invention;

Fig. 2 is a detailed view, partially in section, of the eccentrics utilized to control the energization of the circuit and the means for mounting the eccentrics on a shaft;

Fig. 3 is a timing diagram depicting the period of closure of the pair of contacts and the period of energization of the series circuit;

Fig. 4 is a schematic diagram of a circuit maker and breaker wherein two parallel circuits are alternately energized during a predetermined period of time to control the operation of a pair of apparatuses; and

Fig. 5 is a timing diagram depicting the period of closure of a pair of contacts and the period of energization of one of the control circuits shown in Fig. 4.

Referring to the drawings and more particularly Fig. 1, there is disclosed a constantly rotating electric motor 10 adapted to drive a motor shaft 11 having a gear 12 secured thereto. Meshing with the gear 12 is a gear 13 secured to a shaft 14 having mounted thereon a pair of eccentrics l6 and 17. Means for securing the eccentrics 16 and 17 to the shaft 14 are illustrated in Fig. 2 wherein there is disclosed a collar 18 pinned to the shaft 14 and a cylindrical spacer 19 interposed between the eccentrics 16 and 17. A lock nut 21 is secured on a threaded portion 22 of the shaft 14 to force the eccentric 16 against the collar 18 and the eccentric 17 against the cylindrical spacer 19 and thus hold these elements against rotation relative to the shaft 14.

The eccentric 16 is adapted to reciprocate a strap 23 (Fig. 1) having attached to its free end a rocker arm 26 of a T-lever generally depicted by the reference numeral 27. Attached to each extremity of a cross arm 28 of the T-lever 27 is a contact element 29. Positioned in underlying relationship to the left-hand contact element 29 is a stationary contact or pivot element 31 and positioned in underlying relationship to the right-hand contact element 29 is a contact 32. A notch is formed in the T-lever 27 at the juncture of the cross arm 28 and the rocker arm 27 to accommodate a bent over portion of a lever 33. The opposite end of the lever 33 is bent over to fit within a notch formed within a conductive block 34. The bent over ends of the lever 33 are urged into their respective notches through the instrumentality of an extended tension spring 36.

In a like manner, the eccentric 17 is adapted to impart movement to a strap 42 to reciprocate said strap with simple harmonic motion. Attached to the free end of the strap 42 in a pivoted fashion is a rock arm 44 of a T-lever 19. The T-lever is provided with a pair of cross arms 51 having secured to their respective extremities a pair of contact elements 52. As shown in Fig. 1, the right-hand contact element engages a contact or pivot element S3 and the left-hand contact element 52 is positioned to cooperate with a stationary contact 54. Positioned within a notch formed in the juncture of the cross arms 51 and the rock arm 44 is a bent over portion of a lever 55. The opposite end of the lever 55 is also bent over and is positioned within a notch formed in a conductive block 56. An extended tension spring 57 engages the lever 54 to urge each of the bent over portions of said lever into the respective notches.

When the shaft 14 is rotated, the eccentrics 16 and 1.7 reciprocate their respective straps 23 and 42 to rock the T-levers 27 and 49. Considering now the movement of the T-lever 27; the movement of the rock arm 26 causes the cross arm 28 to pivot in a clockwise direction about the contact or pivot element 31 until the right-hand contact element 29 engages the stationary contact 32, whereupon continued movement of the rock arm 26 causes the cross arm 28 to pivot in a clockwise direction about the stationary contact 32 which now operates as a fulcrum. This movement breaks the engagement of the left-hand contact element 29 with the pivot element 31 at a time when the T-lever is pivoting with maximum velocity. Upon completion of movement of the strap arm 23 in a leftwardly direction, the eccentric reverses the movement of the strap arm 23 to impart a counterclockwise movement to the rock arm 27; consequently the cross arm 28 now pivots in a counterclockwise direction about the stationary contact 32 until the right-hand contact 29 engages the pivot element 31 whereupon continued movement of the rock arm 26 causes the cross arm 28 to pivot and break the engagement of the right-hand contact element 29 with the stationary contact 32. It may be therefore appreciated that the pivot element 31 now acts as a fulcrum for the movement of the T-lever 27.

This arrangement of elements substantially reduces rebounding or bounce between the contact elements 29 and the associated contacts 31 and 32 because the elements move with a modified simple harmonic motion and secondly the contact elements 29 pivot around the contacts which they engage and not about some external pivot point as in the situation of most contact elements previously used. These two effects, a modified simple harmonic motion and the elimination of external pivot points, permits the contact elements to engage and disengage, at high speed, without subsequent rebounding or bouncing of the movable contact element and hence the possibilities of the contact opening prematurely to cause arcing or vibration is eliminated.

The 'T-lever 49 functions in a manner identical with the T-lever 27 and hence its mode of operation need not be repeated at this time.

The circuit which is controlled by the heretofore described arrangement of mechanical elements comprises a conductor 60 connecting the stationary contact 32 with a piece of equipment 61 which is to be controlled. A second conductor 62 extends from the piece of equipment 61 to contact 54. interconnecting the conductive blocks 34 and 56 is a conductor 64.

It may be therefore appreciated that if the righthand contact element 29 is in engagement with the stationary contact 32 and the left-hand contact element 52 is in engagement with the stationary contact 54 a series circuit is completed to the piece of equipment 61 which may be traced from the equipment 61 over the lead 60, through the stationary contact 32, through the right-hand contact element 29, through a section of the cross arm 23, through the lever 33, through the block 34, over the conductor 64, through the block 56, through the lever 55, through a portion of the cross arm 51, through the left-hand contact element 52, through the stationary contact 54, over the conductor 62, to the piece of equipment 61.

As shown in Fig. 1 the eccentrics 16 and 17 operate in phase, thus the phase angle between the eccentrics is Zero and the maximum displacement of the straps 23 and 24 occurs at the same instant. The result being that for 360 revolution of the shaft 14, the right-hand contact element 29 will engage the stationary contact 32 at the same time the contact element 52 will engage the stationary contact 54; thus, the series circuit to the piece of equipment 61 is completed during a 180 revolution of the shaft 14. If it is desired to energize the pi cc of equipment 61 during a shorter period of time all that is necessary is that the phase angle between the eccentrics 16 and 17 be varied by loosening the lock nut 21 and repositioning the eccentrics with respect to each other. By doing this the phase angle is altered, thus the phase angle may be defined as that angle through which the shaft must rotate in order that maximum displacement is successively imparted to the strap arms 23 and 42.

An example of the operating conditions in the series circuit wherein the phase angle is greater than zero is illustrated in Fig. 3. In this figure line A indicates the condition of the contact pair comprising the contact 32 and the contact element 29. The line designated B represents the condition of the contact pair comprising the contact 54 and the contact element 52. The line designated C represents the condition of the energizing circuit to the piece of equipment 61. The condition of the various elements is plotted against the rotation of the shaft 14 indicated in degrees. In this instance, the eccentrics 16 and 17 are adjusted to operate out of phase, hence for the first 120 revolution of the shaft 14 the contact pair 54 and 52 depicted by line B is closed. Upon the shaft 14 rotating 120 the contact pair 29 and 32 is closed and hence the energizing circuit to the piece of equipment 61 is completed. For the next 60 revolution of the shaft 14 both contact pairs are closed hence the energizing circuit to the piece of equipment 61 is maintained, but upon completion :of the 60 revolution the contact element 52 moves from engagement with the contact 54 to interrupt the circuit, consequently, the circuit will remain open for the remainder of the revolution of the shaft 14 and this cycle of operations will reoccur upon each complete revolution of the shaft 14.

In the situation where the eccentrics operate out of phase then the circuit to the piece of equipment 61 is never completed because one contact pair is always opened. Obviously various other closure periods can be obtained by merely varying the phase relationship of the eccentrics between zero and 180.

Attention is directed to Fig. 4 wherein there is shown a modified embodiment of the invention. In this instance the eccentric drive units and the contact assemblies are identical with the units and assemblies disclosed in Figs. 1 and 2, consequently, a detailed description need not be repeated since the same reference numerals are used again in Fig. 4 to designate the same elements appearing in Fig. 1. Further, the mode of operation of these units and assemblies is identical with the aforedescribed mode of operation of the eccentric drive units and contact assemblies shown in Figs. 1 and 2.

The major distinction between the embodiment shown in Fig. 4 and that shown in Fig. l resides in the manner of connecting the control circuits for operating the pieces of equipment. In the modified embodiment the pair of apparatuses 66 and 67 are controlled by the contact assemblies. Considering first the control circuit for the apparatus labelled 66, this circuit can be traced from the apparatus 66, over a conductor 68, over a conductor 69, through the contact 32, through the contact element 29 when engaging contact 32, through a portion of the cross arm 28, through the lever 33, through the block 34, over a conductor 71, over a conductor 77, over a conductor 72, back to the apparatus 66. Another circuit may be also traced from the apparatus 66, over a conductor 68, over a conductor 73, through the contact 53, through the contact element 52, then engaging contact 53, through a portion of the cross arm 51, through the lever 55, through the block 56, over a conductor 74, over the conductor '72, back to the apparatus 66. It may be thus appreciated that the two traced circuits are connected in parallel to control the operation. of the apparatus 66.

Upon actuation of the shaft 14, the eccentrics 16 and 17 act to cyclically close the contact pair 29 and 32 and the contact pair 52 and 53 and the timing of the period of contact closure is controlled again by the phase angle existing between the eccentrics 16 and 17. Referring now to Fig. 5 the line D represents the time of closure of the contact element 29 with the contact 32. The line B represents the time of closure of the contact element 52 with the contact 53. The line F illustrates the duration of delivery of energizing current to the apparatus 66. Each of these lines D, E and F are plotted against degrees of revolution of the shaft 14 as the abscissa.

An examination of Fig. 5 instantly reveals that upon closure of either contact pair included within the parallel circuits for the apparatus 66 results in an energizing circuit being completed for said apparatus. In the example illustrated in Fig. 5, the eccentrics 16 and 17 are connected to the shaft 14 so that the phase angle equals 120. Thus one or the other arms of the parallel circuits will be completed for 300 and hence the circuit will be interrupted for only 60. By varying the phase angle between the eccentrics 16 and 17 from 0 to 180 the period in which the circuit will be interrupted will be varied from 180 to 0 with respect to a single revolution of the shaft 14.

The second apparatus 67 may be also controlled by the eccentric drive unit and contact assemblies utilized to energize the apparatus 66. The apparatus 67 is connected through a control circuit which can be traced from the apparatus, over a conductor 76, over the conductor 77, over a conductor 74, through the conductive block 56, through the lever 55, through a portion of the lever 51, through the right-hand contact element 52, through the contact 53, over a conductor 78, over a conductor 79, back to the apparatus 67. In addition a second energizing circuit for the apparatus 67 can be traced over the conductor 76, over the conductor 71, through the block 34, through the lever 33, through the portion of the cross arm 28, through the left-hand contact element 29, through the contact 31, over a conductor 81, over the conductor 79 back to the apparatus 67. It will be again recognized that these two circuits are in reality a parallel circuit connected through the contact units to the apparatus 67. The duration of closure of this parallel circuit is identical to a period of closure of the parallel circuit associated with the apparatus 66, however, the instant of circuit interruption is 180 out of phase. Manifestly an adjustment of the phase angle between the eccentrics 16 and 17 not only results in a change in the period of closure of the circuits associated with the apparatus 66, but also an identical change in the period of energization in the circuits associated with the apparatus 67.

It is to be understood that the above described arrangements of apparatus and circuits and the construction of the elemental parts are simply illustrative of the application of the principles of the invention and many other modifications may be made without departing from the invention.

What is claimed is:

1. In a circuit maker and breaker, a pair of parallel circuits, a pair of contacts in each arm of each parallel circuit, a first eccentric driven device for controlling one contact pair in each parallel circuit, a second eccentric driven device for controlling the other contact pair in each parallel circuit, a common return circuit connected to both said eccentric driven devices to provide a return for each arm of said parallel circuits, and means for actuating the eccentric driven devices to successively close each contact pair in each parallel circuit during revolution of the eccentric device, said parallel circuits adapted to be energized fora period as determined by the phase angle between the eccentric devices.

2. In a device for energizing a pair of electrical apparatuses, a first parallel circuit for controlling a first one of said electrical apparatuses, a second parallel circuit for controlling a second one of said electrical apparatuses, contact pairs included in each arm of each parallel circuit, each of said circuits having a return circuit running from a contact in each pair to both said apparatuses, a first cyclically operable means for closing and opening a contact pair in the first parallel circuit and a contact pair in said second parallel circuit, a second cyclically operable means for closing and opening a contact pair the first parallel circuit and a contact pair in the second parallel circuit, and means for varying the phase angle between the cyclically operable means to simultaneously vary the period in which said parallel circuits to the respective apparatuses are energized.

3. In a device for energizing a pair of apparatuses, a first parallel circuit for controlling a first one of said electrical apparatuses, a second parallel circuit for controlling a second one of said electrical apparatuses, contact pairs included in each arm of each parallel circuit, a first eccentric drive device for closing and opening a contact pair in the first parallel circuit and a contact pair in the second parallel circuit, a second eccentric drive device for closing and opening the other contact pair in the first parallel circuit and the other contact pair in the second parallel circuit, a common circuit for completing said parallel circuits running from one contact of each pair to both said apparatuses, said eccentric drive devices being adapted to hold said contact pairs closed for 180 of revolution of the respective eccentrics, and means for varying the phase angle between the eccentrics to vary the period of energization of each parallel circuit from 180' to 360 of revolution of the eccentrics.

4. In a device for alternatively actuating a pair of electrical apparatuses, a constantly rotating shaft, a pair of cyclically operable means mounted on said shaft, a pair of driven members associated with individual ones of said cyclically operable means, contact units operated by said driven members, each of said contact units having a pair of stationary contacts and a movable contact spanning said stationary contacts, a first parallel circuit connected to one of said apparatuses and having included in each branch one stationary contact from each of said contact units, a second parallel circuit connected to the other of said apparatuses and having included in each branch the other stationary contact from each of said contact units, and a circuit common to each parallel circuit running from each of said movable contacts to each of said apparatuses for completing said parallel circuits.

References Cited in the file of this patent UNITED STATES PATENTS 1,482,686 Julson Feb. 5, 1924 1,553,657 Zars et al. Sept. 15, 1925 2,157,858 Miller May 9, 1939 2,255,220 Joesting et al. Sept. 9, 1941 2,605,366 Zimmer July 29, 1952 FOREIGN PATENTS 613,418 Great Britain Nov. 29, 1948 

